Impact of CBCT-assessed mandibular anatomy on neurosensory disturbance following sagittal split osteotomy.

INTRODUCTION

This study aimed to evaluate whether specific mandibular anatomical features are associated with postoperative neurosensory disturbance (NSD) in patients undergoing sagittal split osteotomy (SSO) and to identify cone-beam computed tomography (CBCT)-based measurements that may improve preoperative risk assessment.

METHODS

Preoperative CBCT scans and patient-related variables, including demographic characteristics, type of deformity, side, fixation method, and third molar status, were retrospectively evaluated in patients who underwent SSO between 2016 and 2022. Measurements between the mandibular canal and key anatomical landmarks related to SSO were obtained. Neurosensory disturbance of the inferior alveolar nerve (IAN) was assessed using clinical sensory tests and patient-reported assessments. Outcomes were compared between patients with and without NSD.

RESULTS

A total of 52 patients (35 women and 17 men; mean age, 24.2 ± 6.1 years) were included. In univariate analysis, female sex was associated with a higher frequency of NSD. The distance between the lingula and sigmoid notch, total bone thickness inferior to the canal, and cancellous bone thickness buccal to the canal at the mesial aspect of the second molar were significantly shorter in patients with NSD. At the distal aspect of the second molar, total bone thickness buccal and inferior to the mandibular canal, as well as cancellous bone thickness inferior to the canal, were also significantly reduced. However, none of these variables remained significant in multivariate analysis.

CONCLUSIONS

Although no independent predictive factor for NSD was identified, female sex and reduced mandibular canal-related bone dimensions may be associated with a higher incidence of postoperative NSD. Preoperative CBCT evaluation of these parameters may support surgical planning and help reduce the risk of inferior alveolar nerve injury.